1. Field of the Invention
This invention relates generally to an assembly of components in a hollow polymer tank and, in particular, to attaching components to the surface of a wall within a tank.
2. Description of the Prior Art
Currently components such as valves are hot plate-welded to the outer surface of a polymer fuel tank. To accomplish this, a hole is bored through the tank wall, which includes a barrier layer. The breaching of the barrier layer and the construction of the current hot plate welded valves increase permeation of the tank shell.
External hot plate welding is acceptable for current emission requirements; however as emission regulations get stricter, it is necessary to place the valves inside the fuel tank to avoid boring through the fuel tank wall.
Newly developed technologies, which can be difficult and costly, focus on installing the valves during the molding process.
Internal hot plate welding of components is encumbered by limited access through the opening, such as is required for the fuel delivery module (FDM). The need to heat both the tank and component surface in hot plate welding requires multiple robotic manipulations; therefore, the process, has limited application.
Hot plate welding in the tanks imposes requirements and limitations on the design of the component to be attached to the interior of a tank that are difficult to realize. For example, in hot plate welding, a significant amount of mass is required at the weld site so that the mass is melted separately from the fuel tank surface. After the component and tank wall are heated to a molten state, they must retain heat and remain molten while the hot plate is removed from the tank, the component is inserted and joined under force, and the molten pools fuse together to create the weld.